Tule fog (/ ˈ t uː l iː /) is a thick ground fog that settles in the San Joaquin Valley and Sacramento Valley areas of California's Central Valley. Tule fog forms from late fall through early spring (California's winter season) after the first significant rainfall.

Jan 11, 2020 · Opaque tule fog, a staple of winter in California’s Sacramento and San Joaquin valleys, is the bane of motorists because it can reduce visibility to zero and cause massive freeway pileups.

Feb 24, 2022 · This fog isn’t the type that rolls in from the ocean, or wraps curling tendrils around hillsides. Tule fog is not the mist in a horror movie, parting to reveal a monster.

Nov 6, 2022 · According to KGET chief weather forecaster Kevin Charette, tule fog forms when ground moisture, usually after a heavy rain, is present and the air begins to cool, saturating the moisture and creating fog from the ground up. Overnight, you …

Jan 16, 2024 · Tule fog is a type of radiation fog and is named after the tule grass that grows along waterways, such as the California Delta and the many rivers across the Central Valley that join together...

Apr 10, 2019 · The Central Valley’s heavy wintertime tule fog – known for snarling traffic and closing schools — has been on the decline over the past 30 years, and falling levels of air pollution are the cause, says a new study by scientists at the University of California, Berkeley.

Apr 12, 2019 · For those who haven't heard of the term before, thick fog called "Tule Fog" traditionally forms in the Southern Central Valley of California, but it's become less common in recent years.

Jun 12, 2014 · Named after the tule grass wetlands (tulles) found in the area, the Tule Fog is a radiation fog caused by the combination of a high relative humidity (typically after a heavy rain), calm winds, and rapid cooling during the night.

May 22, 2014 · For California's highway managers, research showing a decline in the Central Valley's unique tule fog is no surprise. The thick ground fog, an iconic weather feature that settles in the San...

Dec 18, 2024 · The phenomenon is known as tule fog. It’s different from the marine layer that often blankets the city in summer months, and it can be hazardous. Drivers frequently encounter visibility of less than a quarter-mile, and changes in conditions can be abrupt.